Job Description
Dev / Senior Developer
The Dev / Senior Developer is the primary builder for both Lambda services, the shared client library, Kafka producer logic, and backfill tooling. This role requires strong backend engineering skills with hands-on AWS serverless experience.
Required Skills
- .NET: 4+ years production experience in the primary Lambda runtime; ability to write clean, testable, well-structured code with proper error handling and logging using AWS Lambda's .NET managed runtime (Amazon.Lambda.Core).
- AWS Lambda & serverless: Practical experience building and deploying Lambda functions, including timeout management, concurrency configuration (reserved and provisioned), cold-start optimization, and Step Functions for orchestration; familiarity with Lambda deployment via AWS SAM or CDK and monitoring via CloudWatch Logs and Lambda Insights.
- REST API integration: Experience consuming third-party REST APIs with pagination, rate-limit handling, retry/back off strategies, and authentication (API key headers); ability to store and rotate API credentials securely using AWS Secrets Manager or Parameter Store. Familiarity with marketing platform APIs is a plus.
- Apache Kafka: Hands-on experience producing messages to Kafka topics on Amazon MSK, including AVRO serialization, Schema Registry integration, producer configuration (acks, retries, idempotency), and troubleshooting publish failures.
- AVRO & Schema Registry: Ability to define, version, and register AVRO schemas; understanding of schema evolution (backward/forward compatibility) and contract-first design.
- Amazon DynamoDB: Experience designing table schemas (partition/sort keys), managing read/write capacity, implementing TTL policies, and using DynamoDB for cursor/state persistence and configuration storage; familiarity with DynamoDB conditional writes for idempotent operations.
- Data pipeline design: Understanding of batch/incremental ingestion patterns, idempotency strategies (composite keys, deduplication), cursor-based change tracking, and data correctness in distributed systems; experience using SQS as a buffer between pipeline stages for resilience and flow control.
- Testing: Strong unit testing discipline; experience with integration testing using mocks, stubs, or sandbox environments for external APIs and Kafka; familiarity with running integration tests against local AWS service emulators (LocalStack) or AWS sandbox accounts.
Desirable
- Experience with Snowflake or data warehouse ingestion patterns.
- Familiarity with API v2 (contacts, lists, list changes endpoints).
- Experience with historical backfill tooling (phased execution, rate-limit-aware replay).
- Knowledge of PII handling and data minimization in event-driven architectures, including AWS KMS encryption and CloudWatch log filtering for sensitive fields
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